DD247262A1 - ARRANGEMENT FOR PREPARING BROKEN RAW BROWN CARBON FOR A CARBURNING STEEL - Google Patents

Abstract

The invention relates to an arrangement for processing cracked raw lignite coal for a pulverized coal firing, wherein between feeder and coal dust mill a fine material separation device and a coarse material drying device is involved. Here, the fines separation and the coarse material drying should be included directly in the process of coal dust firing. This is achieved by integrating the feeder into the fines separating device having a medium-loaded classifying base and connecting the fine-material separating device via a transport device to the coarse-material drying device having a medium-loaded grate and a medium-loaded transport device arranged above it, the subfloor located underneath the classifying tray Part of the fine material separator is connected via a acted upon by a transport medium line with a pulverized coal burner of pulverized coal firing. figure

Description

For this 2 pages drawings

Field of application of the invention

The invention relates to an arrangement for processing cracked raw lignite coal for a pulverized coal firing, wherein between feeder and coal dust mill «fine material separator and a coarse material drying device is involved.

Characteristic of the known technical solutions

The burning of ballast-rich and moist raw lignite coal in pulverized coal firing suffers from considerable deficiencies, starting with the mill wear, the power reduction of mills and the firing up to strong ignition and combustion instabilities.

Through a variety of measures was tried, the o.g. To turn off the defect.

Of particular importance is the predrying of the moist raw lignite coal and / or the separation of the ballast-rich lignite coal. In principle, a fine material separating device and a coarse material drying device are integrated directly or indirectly in front of the pulverized coal mill.

However, it has been found that no high level of effectiveness of the overall technology can be achieved, since high plant and operating expenses only face minor treatment advantages.

For this reason, it is dispensed with a separate preparation and tried with the help of gas, oil or coal dust-powered support burners to ensure stable combustion.

Object of the invention

The aim of the invention is to achieve a technically simple and effective treatment.

Explanation of the essence of the invention

The invention has for its object to include the fines separation and Grobguttrocknung directly in the process of pulverized coal.

This is achieved in that according to the invention the feeder is integrated into a fine-grained separating tray having a medium-loaded classifying plate and the fine-material separating device is connected via a transporting device to a coarse-feed drying device having a medium-loaded grate and a medium-loaded transport device arranged above it, the underside of the classifying tray located part of the fine material separator is connected via a acted upon by a transport medium line with a pulverized coal burner of pulverized coal firing.

embodiment

In one embodiment, the invention is explained in detail. The drawing shows:

-2- IAI ZOEC

Fig. 1: the arrangement of the fine material separator and the coarse material drying device within the coal dust firing

for a steam boiler in principle, Fig. 2: the formation of the coarse material drying device in principle.

In the combustion chamber 20 of the boiler, the flue gas recirculation 2 with coal dust mill 3 and coal dust main burner 4 is integrated (Fig. 1).

The allocator 6 is integrated via the shaft 7 in the fine material separator 8, in which the classifying 9 is arranged. The funnel 14 of the fine material separator 8 is integrated via the ejector 16 into the conduit 17 and via the pulverized coal burner 19 into the combustion chamber 20.

The upper part 23 is connected via the line 22 to the combustion chamber 20.

The fine material separating device 8 is connected via the transport device 25 with the coarse material drying device 12, in which the grate 28 with overlying transport device 31 (traveling grate, scratches) is arranged. The lower part 27 of the coarse material drying device 12 is connected via the line 26 to the combustion chamber 20. The upper part 35 of the coarse material drying device 12 is connected via the exhaust pipe 32 to the exhaust system 33 of the steam boiler 1.

The coarse material drying device 12 has, as a cooling or heating grate 28, the membrane tube wall 36 (FIG. 2), the tubes of which are acted upon either by a heating or cooling medium. The webs 30 of the membrane tube wall 36 have the passage openings 29. The tubes of the membrane tube wall 36 are provided with the rectification directions 34. The mode of action is the following:

The broken raw lignite 5 is fed via the allocator 6 and shaft 7 of the fines separator 8. Due to the arranged Klassierboden 9, the raw lignite 5 is largely loosened up by the hot gas 21 so that the coarse material flow 11 and the fine material flow 10 are formed. This Strombildun ^ is particularly supported by the ejector 16 (suction).

The fine material flow is fed via funnel 14, ejector 16 and line 17 to the pulverized coal stream 19 incorporated in the combustion chamber 20. The fines burn in the combustion chamber 20 stable. It is readily possible that the ejector 16 sucks bunkered coal dust 18 via line 37.

The coarse material 11 passes via the transport device 25 to the transport device 31 in the coarse material drying device 12. About the power 26 20 hot gas 24 is conveyed from the combustion chamber into the lower part 27 and passes through the openings 29 of the membrane tube wall 36 and the transport device 31st

By the hot gas 24, the coarse material 11 is dried. By the sliding means 34 it is achieved that the transport device slides as close as possible to the tube wall surface, without the tubes of the membrane tube wall 36 wear.

Corresponding to the transport device 31, the sliding device distance is selected, so that two or more supports are formed.

The dried coal is fed via the transport line 13 of the pulverized coal mill 3 or the chute. The generated coal dust has a high degree of dryness and burns stable. The invention achieves the following advantages:

By dividing the drying plant into two functionally separated functional parts connected in series, in the first stage, with a relatively short residence time, it is possible to maintain the finest grain. In contrast, in the second stage of the process, a degree of drying is determined and varied with a substantially longer drying time. The retention of fine grain and the drying in the first process step takes place in the case of gas flow on all sides, whereby the fine grain and the drying gas are blown into the combustion chamber. In the second stage of the drying operation, the coarse-grained raw coal (after the fine dust exposure) is dried statically on a grate with a high residence time. During this drying process, the coarse moisture is expelled; the residence time is chosen so that no degassing occurs. The dry gas after passing through the drying bed is sucked into the exhaust system of the boiler. This gas has only a very small proportion of combustible. The entire drying process is associated with a steam boiler and is constantly under inert gas operation. Through the membrane tube bed, the bed temperature is adjusted with the appropriate amount of cooling water. With a boiler to be approached, the tubes of the drying bed are flown with a heating medium. Thus, the resulting vapor is sucked by the natural draft. The high degree of drying of the coal for the start-up operation can thus take place before the actual boiler operation.

Claims (9)

Invention claim: 1. Arrangement for processing cracked raw lignite coal for a coal firing, wherein between feeder and coal dust mill a fine material separator and a coarse-dry device is involved, characterized in that the allocator involved in a medium-sized classifying bottom having fines separator and the fines separator over a transport device to which a medium-loaded grate and a medium-loaded transport device having a coarse material drying device is connected, wherein the part of the fine material separating device located below the classifying plate is connected to a coal dust burner of the pulverized coal firing via a line acted upon by a transport medium. 2. Arrangement according to item 1, characterized in that the grate is formed from a membrane tube wall provided with passages in the webs. 3. Arrangement according to item 1, characterized in that the fine material separating device and the coarse material drying device is connected via a hot gas line to the combustion chamber of the pulverized coal firing. 4. Arrangement according to item!, Characterized in that the located under the Klassierboden part of the fine material separating device is connected to a line acting on the compressor or ejector. 5. Arrangement according to item 1, characterized in that the coarse material drying device is connected via an exhaust pipe to the exhaust system of pulverized coal firing. 6. Arrangement according to item 1 and 4, characterized in that in the line a coal dust loaded line is involved. 7. Arrangement according to item 1 and 2, characterized in that the grate has an attached sliding device. 8. Arrangement according to item 1 to 7, characterized in that the allocator is integrated via an adjusting device in the fine material separating device and in the pulverized coal mill. 9. Arrangement according to item 1,4,6, characterized in that the line is incorporated in a separate burner.